Method of making plastic covered keys for musical instruments



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4 Sheets-Sheet 2 Fig 5 INVENTOR.

Donald K Good M W Oct. 23, 1962 GOOD 3,060,074

METHOD OF MAKING PLASTIC COVERED KEYS FOR MUSICAL INSTRUMENTS Filed Feb. 2'7, 1958 4 Sheets-Sheet 3 Fig 6 I M IN VEN TOR.

Dona/a K 6004 M f M Oct. 23, 1962 v K, oon 3,060,074

METHOD OF MAKING PLASTIC COVERED KEYS FOR MUSICAL INSTRUMENTS Filed Feb. 27, 1958 4 Sheets-Sheet 4 INVENTOR. Dana/d 1f. 600d United States Patent 3,060,074 METHOD OF MAKING PLASTIC COVERED KEYS FOR MUSICAL INSTRUMENTS Donald K. Good, Ivoryton, Conn., assignor to Pratt,

Read & C0., Incorporated, Ivoryton, Conn., a corporation of Connecticut Filed Feb. 27, 1958, Ser. No. 717,931 2 Claims. (Cl. 156--250) This invention relates generally to the manufacture of keys for musical instruments and more particularly to the method of making keys having the base thereof formed of wood or the like with a covering formed of molded plastic material. This application is a continuation-inpart of my application Serial No. 541,481, filed October 19, 1955, now abandoned.

In the prior art, it has been customary to provide keys for musical instruments, such as pianos, which are formed of wood with a covering of ivory thereon to provide an attractive appearance and a smooth comfortable feel to the person playing the instrument. Such keys are provided by first forming a rough keyboard by securing together pieces of wood and cutting the same to the required size. Then pieces of ivory are secured to the front of the keyboard and other pieces of ivory are secured to the top thereof. The keys are then cut apart and the ivory covering is formed and polished to provide the finished form. It is apparent that the foregoing constitutes a tedious, time consuming, and expensive construction. Although other materials have been used for covering, in addition to ivory, the method followed in providing the construction has remained the same.

It is, therefore, an object of the present invention to provide an improved method and apparatus for making keys for musical instruments.

A further object is to provide a method of constructing covered piano keys wherein the covering for the keys is formed to a greater extent prior to assembly to reduce the assembly operation and the forming required thereafter, to thereby simplify the over-all construction.

Another object of the invention is to provide apparatus for applying plastic covering to keys for musical instruments wherein a secure connection is provided in a simple manner.

A feature of the invention is the provision of a method of manufacturing keys for musical instruments wherein a rough keyboard is formed and plastic covering pieces are molded having integral front and top portions with the top portions having rounded overhanging edges of the desired configuration to thereby reduce the finishing operations.

A further feature of the invention is the provision of plastic covered keys wherein covering pieces for a plurality of keys, as for an octave, may be molded as a single unit to simplifyhandling and assembly, and the molded covering is cemented to a rough keyboard with heat and pressure being applied thereto through a heat conducting plate shaped to protect the edges of the plastic covering.

A still further feature of the invention is the provision of a plastic covering for a rough keyboard which is drilled and stamped to define individual keys, wherein the covering is molded as a single piece for covering the natural keys of an octave and has openings corresponding to the sharp keys and grooves on the covering surface outlining the natural keys, with the covering being positioned on the keyboard by aligning the openings in the covering with the openings in the rough keyboard, and the individual keys being cut out along the grooves in the covering and the marks stamped on the rough keyboard.

Another feature of the invention is the provision of apparatus for securing plastic covering pieces having inte- 3,060,074 Patented Oct. 23., 1962 ice front covering portions and pressure means for holding the plate against top and front heating units to apply heat and pressure through the plate to the plastic covering.

Further objects, features, and the attending advantages of the invention will be apparent from a consideration of the following description when taken in connection with the accompanying drawings wherein:

FIG. 1 illustrates a piano keyboard including keys made in accordance with the invention;

FIG. 2 illustrates the plastic covering as placed on a rough keyboard;

FIGS. 3 and 4 are top and end views of a molded plastic covering piece for the natural keys of an octave;

FIG. 5 is a chart showing the steps taken in followingthe method in accordance with the invention;

FIG. 6 illustrates a press for securing the molded plastic covering to a rough keyboard;

FIG. 7 is a detail view of the pressure plate used in the press shown in FIG. 6; i

FIG. 8 is a perspective view of a keyboard and covering foming another embodiment of the invention;

FIG. 9 is a cross-sectional view along the line 99 of FIG. 8; and

FIG. 10 is a top view of a covering piece as shown in FIG. 8.

In accordance with the invention, keys for musical instruments, such as pianos, are provided by placing molded plastic covering pieces on a rough keyboard. The rough keyboard may be provided by end-gluing together kiln dried pieces of wood material which are first milled to the required width, length, and thickness, with the glued boards being planed and sanded to more precise dimensions. The keyboard is drilled for the various pins and stamped to mark the individual keys. The covering is provided by molding plastic material to form covering pieces having integral front and top parts for the white or natural keys. Each covering piece may cover a plural- 'ity of keys, as the keys of an octave, with pieces for one and two key being provided at the ends to form a standard keyboard. The top parts of the covering pieces as molded extend beyond the front parts thereof, and have rounded edges to provide the desired finished configurations to eliminate usual finishing operations. The plastic covering pieces for a key board are cemented to the front and top of a rough keyboard and then a pressure plate is provided over the plastic pieces. The covered keyboard and pressure plate are placed in a press which provides pressure through the plate to the front and top parts of the covering pieces. The press includes steam chambers for applying heat to the front and top parts of the covering pieces through the pressure plate. The covered keyboard is then trimmed at the sides and cut into individual keys bysawing operations. The covered white keys are shaped, sanded, and polished to provide completed keys. The short or sharp keys have tops placed thereon and are finished.

The covering pieces may have grooves molded in the top and front portions thereof to define the individual natural keys. The individual keys may then be cut out along the grooves in the covering and along the marks stamped in the rough keyboard. The openings in the covering at the positions of the sharp keys may be aligned with the front pin holes for the sharp .keys which are drilled in the rough keyboard, to thereby accurately position the covering on the rough keyboard.

Referring now to the drawings, in FIG. 1 there is shown the keyboard for a standard piano having 88 keys in all. This includes 52 natural or white keys 10, and 36 sharp or black keys 11, As is well known, the black keys are aoeepm 3 shorter and extend above the White keys. FIG. 2 illustrates the construction of the keys of a keyboard wherein the keys are formed by a rough keyboard serving as a base on which plastic covering pieces 16, 17, and 18 are provided. The covering piece 16 covers a single natural key at the right end of the keyboard. A plurality of cov- I ering pieces 17 are provided, each of which covers the seven white keys of an octave. As the standard keyboard includes seven complete octaves, seven covering pieces as represented by the reference numeral 17 are required. In FIG. 2 only one complete piece 17 is shown and the keyboard is broken away to represent the additional pieces. At the left end of the keyboard, the piece '18 covers the two natural keys which extend beyond the last complete octave.

FIGS. 3 and 4 show more in detail the construction of the covering pieces 17 of FIG. 2. FIGS. 3 and 4 will also facilitate understanding of the exact construction of the plastic covering pieces 16 and 18. It will be apparent from FIGS. 3 and 4 that the top part 20 and the front part 21 of the covering are molded as a single integral unit. The keys include front overhanging portions 22 having rounded corners 23 as is the accepted configuration for piano keys. The dot-dash lines 24 of FIG. 3 show the dividing lines between the individual keys and the keyboard will be cut along these lines to separate the individual keys.

It will be noted that a flat portion 25 is provided between the rounded corners 23 of adjacent keys, and this flat portion has a width equal to the width of the cut which will be required to separate the keyboard into individual keys. Accordingly, the rounded corners will join the edges of the keys so that the corners of the keys intermediate the octave will have the same configuration as the corners of keys at the ends of the octave as shown at 26. By molding the covering in this shape, the desired finished key configuration is provided without any cutting of the plastic covering after the keys are individually cut apart.

Reference is now made to FIG. 5 which shows the steps required in constructing plastic covered keys in accordance with the invention. The steps are divided into four main steps each of which includes a plurality of intermediate steps. Main step I relates to the construction of the rough keyboard '15- of FIG. 2. The steps for making up this rough keyboard are known in the art and do not constitute a part of the invention. However, to completely describe the overall process utilized, these steps are shown in FIG. 5. It will be apparent that certain variations in the steps may be provided but the steps listed, or equivalent steps, will be required.

Main step II relates to the making of the plastic covering pieces. In accordance with the invention, the covering pieces have integral top and front portions, and pieces of such configuration are provided by molding operations.

Step III covers the securing of the molded pieces on the rough keyboard. The intermediate steps required are fully set forth in FIG. Sand the apparatus required is illustrated in FIGS. 6 and 7. First, cement is spread on the front and top surfaces of the rough keyboard 15 and then the plastic pieces are placed thereon in the positions as shown in FIG. 2. Handling of the key covering is greatly simplified by having molded pieces with integral top and front parts. In the previous practice, pieces for the front and top were cut from fiat stock and placed separately on the rough keyboard.

A pressure plate is then placed over the plastic covering pieces to apply pressure and heat thereto. The plate 30 is made of a suitable material such as aluminum, rubber coated steel, polished or plated steel, or stainless steel. When made of aluminum, the inner surfaces 31 and 32 of the plate, which contact the key covering pieces, are polished and then the plate 30 is anodized. This provides a very smooth surface for contact with the plastic covering pieces so that the covering pieces will not be scratched or otherwise marred by the pressure plate. The pressure plate has a cutaway portion 33 to receive the overhanging edges 22 of the plastic coverings. The corners 34 and 35 of the pressure plate are rounded to further prevent marking of the plastic covering pieces.

The rough keyboard with covering pieces thereon and the pressure plate positioned on the covering pieces is placed in a press as shown in FIG. 6. The press has a base plate 40 on which the rough keyboard 15 may be positioned. The plate 40 is mounted on a frame structure 41 which may be raised and lowered by suitable means such as a hydraulic cylinder, a screw, etc. The hydraulic cylinder 42 is shown for this purpose and raises the plate 40 and the keyboard thereon so that the top surface of the pressure plate 30 comes into engagement with a heating unit such as a steam or hot water chest, an electric heater, or the like. A steam chest 43 is illustrated for providing heat and is supported in fixed position so that pressure may be applied thereagainst. A second movable member, illustrated as a hydraulic cylinder 44, is supported on the frame structure 41 and is adapted to force the rough keyboard 15 to the left so that the front edge of the pressure plate bears against steam chest 45. A second heating unit, illustrated as steam chest 45, is in fixed position on the frame 41 so that the cylinder 44 may cause the rough keyboard 15 to exert any desired pressure on the front part 21 of the plastic covering which is held in fixed position by the surface 32 of the pressure plate 30 which is, in turn, held by the steam chest 45. The cylinder 42 may then be again operated to provide the desired pressure of the keyboard 15 against the top surface 20 of the key covering.

The steam chests 43 and 45 provide heat which is transferred through the pressure plate 30 to the key covering so that heat and pressure operate together on the cement to provide a secure bond between the plastic covering and the rough keyboard. In the process which has been used, the steam chests provide a temperature of F. The side hydraulic cylinder has been operated to provide a pressure of 230 pounds per square inch between the front of the keyboard and the covering. A pressure of 106 pounds per square inch has been used between the top of the keyboard and the covering. The pressure has been held for 1 /2 minutes, which at the temperature used has been found to provide a secure bonding effect. The hydraulic cylinders may then be released to remove the pressure to permit removal of the plate from the covered keyboard, and also to permit removal of the keyboard from the press. The temperature, pressures, and time specified above merely illustrate one process in accordance with the invention and other values may be used as required in individual cases.

After the covered keyboard is removed from the press, main step -IV as indicated in FIG. 5 may take place. The ends of the keyboard 15 are first trimmed to the desired size. Then the boards with the covering thereon are sawed into individual keys. This will require sawing between the plastic pieces such as between pieces 16 and 17 of FIG. 2, and also sawing through the plastic coverings along the lines 24 as shown in FIG. 3. A band saw may be used to cut out the individual keys and both the white or natural keys, which are covered by plastic, and the short or sharp keys, which are not covered, are produced from the keyboard.

The covered white keys are shaped, sanded, and polished to provide the final finished form. It is to be pointed out, however, that this operation is greatly simplified over that required when using ivory or other covering provided in the form of fiat plates which are not preformed to the desired configurations. In such case, the rounded corners must be provided at this stage and the edges must be finished, whereas by using plastic covering molded to the desired configuration, such steps are not required. The tops may be bonded to the short or sharp keys and these keys may be painted or covered 'to provide the black appearance which is standard construction.

The keys are then placed on key frames having front and balance rails and pins so that they assume the same positions as when mounted on the keyframe of the musical instrument for which they are intended. When mounted on the frame, the keys may be squared up, leveled, spaced, etc. Thereafter, the finished keys may be inspected, packed, and shipped for use as may be required. i

FIGS. 8, 9, and illustrate a keyboard construction which conforms generally to the construction which has been described in which the covering pieces are molded with grooves defining the individual natural keys. The rough keyboard lS is shown in more detail in FIG. 8 than in FIG. 2. As previously stated, the rough keyboard, when formed, is stamped as shown by lines 46 to mark the individual keys. Holes 47 are drilled or punched to receive the balance pins in the keybed and holes 48 are provided for connection of an abstract or capstan to the keys. Holes are also drilled at the front of the keys to receive the front guide pins on the keybed. The holes 49 for the natural keys are shown dotted since they appear under the covering. The holes 59 for the sharp keys appear at the slots in the covering as will be further explained.

Covering pieces 50, 5 1, 52, and 53 are shown on the rough keyboard and each piece covers the seven natural keys of an octave. Each covering piece is molded with openings or slots at the rear thereof corresponding to the sharp keys, and with grooves or recesses 55 on the top surfaces thereof to mark the individual natural keys. The portions of the covering pieces between the slots correspond to the rear parts of the individual natural keys. As shown in FIG. 8, the covering pieces are molded so that the portions between the slots and the grooves in the covering pieces define individual natural keys which correspond to the individual natural keys defined by the marking on the rough keyboard. In addition to the grooves 55 on the top surface of the covering, similar grooves '56 may also be provided in the front surface of each key covering. The rounded corners 61 of the overhanging parts 60 of the covering pieces meet with the grooves 55, all of which are molded in the covering pieces, to completely outline the keys so that the shape of the keys is completely controlled by the molding of the covering pieces. This results in highly uniform key configuration.

As previously stated, the rough keyboard is drilled to provide the various holes required in the keys. As the covering pieces are molded with openings or slots 58 therein to provide spaces for the sharp or short notes, the front pin holes 59 for the sharp notes appear in these openings. By centering the openings in the covering pieces with respect to the sharp front pin holes, accurate positioning of the covering pieces on the rough keyboard is easily accomplished.

The grooves 55 and 56 on'the key covering, together with the lines 46 on the rough keyboard, facilitate the sawing of the covered keyboard into individual keys. The heads of the keys are sawed along the grooves 55a, 55b, 55c, 55d, and 552 which extend back to the sharp openings. These five cuts may be made by a single multi-sawing operation. A cut is made from the front of the keyboard back along the groove 55 to separate the tails of the adjoining natural keys. Similarly, a cut is made at 62 between the key covering pieces 50' and 51.

To completely sever the keys, the portions of the rough keyboard 54 which form the sharps are cut out by a band sawing operation. The front end of the sharp key portions, underneath the sharp openings 58 in the covering, may be cut or punched when the rough keyboard is formed to facilitate band sawing of the sharp keys. These cuts also serve to help locate the covering pieces on the rough keyboard. After the sharp keys are cut out, they have the tops bonded thereto and are finished as previously described.

The natural keys are also finished but as the overhanging parts have rounded edges molded thereon, which meet with the grooves molded in the top surface, an even outline for the keys is provided in the molded covering.- The marks on the covering clearly define the lines to be cut so that the keys can be sawed very accurately. Accordingly, the keys when out apart are of such even shape that little finishing is required.

The improved method in accordance with the inven tion has been found to result in a substantial saving in the cost and time required in the manufacture of keys for musical instruments. This is accomplished by molding the coverings so that the final configuration is provided and since pieces are used which cover a plurality of keys, the handling and assembly operations are greatly simplified. By molding the top and front parts of the key covering as an integral unit, handling and assembly are further simplified. Also, the resulting construction is improved since more secure bond of the covering to the keyboard is maintained and the tendency of the front or top portion to loosen is reduced because of this integral construction of the covering pieces.

What is claimed is:

l. The method of making the natural keys for musical instrument keyboards which include natural keys and sharp keys and wherein a preformed plastic covering is provided on the exposed top and front surfaces of the natural keys, such method including the steps of, forming a rough keyboard of a length to provide a plurality of keys, stamping the rough keyboard to mark the individual keys, drilling spaced openings through the rough keyboard which are positioned in the individual keys, molding unitary plastic covering pieces for the front part of the natural keys of the keyboard each in a shape with a front portion and an integral top portion having an overhanging edge with grooves therein having rounded corners to define individual keys, at least one of said covering pieces being molded in a shape to cover all the naturalkeys of an octave and with rear slots positioned to correspond to spaces occupied by the sharp keys of the octave to form extending parts shaped to correspond to the natural keys, the grooves and slots in the covering pieces defining individual keys which correspond to the marking of the individual keys on the rough keyboard, applying adhesive on the top and front surfaces of the rough keyboard, placing the plastic covering pieces on the rough keyboard with the top and front portions thereof engaging the adhesive on the top and front surfaces of the keyboard, aligning the slots in the covering pieces with the markings on the rough keyboard so that the extending parts are positioned on the individual natural keys marked on the rough keyboard, applying heat and pressure simultaneously to the top portion and to the front portion of the plastic covering to secure such top and front portions of the covering to the top and front surfaces of the rough keyboard, cutting the keyboard and plastic covering pieces thereon from the grooves in the overhanging edge of the covering pieces and along the marks on the rough keyboard whereby the individual natural keys when severed have parts of the covering pieces on the top and front surfaces thereof, and finishing the individual keys.

2. The method of making the natural keys for musical instrument keyboards which include natural keys and sharp keys interspersed therewith and wherein a preformed plastic covering is provided on the exposed top and front surfaces of the front parts of the natural keys, such method including the steps of, securing together pieces of wood to form a rough keyboard of a length to provide all the keys of the keyboard, stamping the rough keyboard to make the individual keys, drilling openings through the rough keyboard spaced to conform to the individual keys, molding unitary plastic covering pieces for the front parts of the natural keys of the keyboard each in a shape with a front portion and an integral top portion having an overhanging edge With grooves therein having rounded corners to define individual keys corresponding to the individual keys marked on the rough keyboard, and with at least one of said covering pieces having an extent to cover the natural keys of an octave with rear slots therein which correspond to spaces occupied by the sharp keys to form extending parts shaped to correspond to the natural keys as marked on the rough keyboard, applying adhesive on the top and front surface of the rough keyboard, placing the plastic covering pieces on the rough keyboard with the top and front portions thereof engaging the adhesive on the top and front surfaces of the keyboard, aligning the slots in the covering pieces with the markings on the rough keyboard so that the extending parts are positioned on the individual natural keys marked on the rough keyboard, placing a removable pressure plate over the plastic covering in engagement with the top and front portions thereof, applying heat and pressure through the pressure plate simultaneously to the top portion and to the front portion of the plastic covering to secure such top and front portions of the covering to the top and front surfaces of the rough keyboard, removing the pressure plate from the keyboard, cutting the keyboard and plastic covering pieces thereon from the grooves in the overhanging edge of the covering pieces and along the marks on the rough keyboard whereby the individual 8' natural keys when severed have parts of the covering pieces on the top and front surface thereof, and finishing the individual keys.

References Cited in the file of this patent UNITED STATES PATENTS 32,972 Browne Aug. 6, 1861 165,024 Pratt June 29, 1875 174,001 Pratt Feb. 22, 1876 174,002 Pratt Feb. 22, 1876 210,780 Hyatt Dec. 10, 1878 251,212 French Dec. 20, 1881 271,120 Rikeman Jan. 23, 1883 274,328 Hoggson et al. Mar. 20, 1883 423,075 Newell Mar. 11, 1890 483,378 Fuller Sept. 27, 1892 665,989 Bechtold Jan. 15, 1901 770,114 Romunder Sept. 13, 1904 2,026,692 McDaniel Jan. 7, 1936 2,031,418 Kraft Feb. 18, 1936 2,344,488 Bowling Mar. 21, 1944 2,392,734 Haberstump Jan. 8, 1946 2,584,319 Appel Feb. 5, 1952 2,720,245 Reinhard Oct. 11, 1955 FOREIGN PATENTS 569,548 Great Britain May 29, 1945 249,145 Switzerland Mar. 16, 1948 

1. THE METHOD OF MAKING THE NATURAL KEYS FOR MUSICAL INSTRUMENT KEYBOARDS WHICH INCLUDE NATURAL KEYS AND SHARP KEYS AND WHEREIN A PREFORMED PLASTIC COVERING IS PROVIDED ON THE EXPOSED TOP AND FRONT SURFACES OF THE NATURAL KEYS, SUCH METHOD INCLUDING THE STEPS OF, FORMING A ROUGH KEYBOARD OF A LENGTH TO PROVIDE A PLURALITY OF KEYS, STAMPING THE ROUGH KEYBOARD TO MARK THE INDIVIDUAL KEYS, DRILLING SPACED OPENINGS THROUGH THE ROUGH KEYBOARD WHICH ARE POSITIONED IN THE INDIVIDUAL KEYS, MOLDING UNITARY PLASTIC COVERING PIECES FOR THE FRONT PART OF THE NATURAL KEYS OF THE KEYBOARD EACH IN A SHAPE WITH A FRONT PORTION AND AN INTEGRAL TOP PORTION HAVING AN OVERHANGING EDGE WITH GROOVES THEREIN HAVING ROUNDED CORNERS TO DEFINE INDIVIDUAL KEYS, AT LEAST ONE OF SAID COVERING PIECES BEING MOLDED IN A SHAPE TO COVER ALL THE NATURAL KEYS OF AN OCTAVE AND WITH REAR SLOTS POSITIONED TO CORRESPOND TO SPACES OCCUPIED BY THE SHARP KEYS OF THE OCTAVE TO FORM EXTENDING PARTS SHAPED TO CORRESPOND TO THE NATURAL KEYS, THE GROOVES AND SLOTS IN THE COVERING PIECES DEFINING INDIVIDUAL KEYS WHICH CORRESPOND TO THE MARKING OF THE INDIVIDUAL KEYS ON THE ROUGH KEY BOARD, APPLYING ADHESIVE ON THE TOP AND FROMT SURFACES OF THE ROUGH KEYBOARD, PLACING THE PLASTIC COVERING PIECES ON THE ROUGH KEYBOARD WITH THE TOP AND FRONT PORTIONS THEREOF ENGAGING THE ADHESIVE ON THE TOP AND FRONT SURFACES OF THE KEYBOARD, ALIGNING THE SLOTS IN THE COVERING PIECES WITH THE MARKINGS ON THE ROUGH KEYBOARD SO THAT THE EXTENDING PARTS ARE POSITIONED ON THE INDIVIDUAL NATURAL KEYS MARKED ON THE ROUGH KEYBOARD, APPLYING HEAT AND PRESSURE SIMULTANEOUSLY TO THE TOP PORTION AND TO THE FRONT PORTION OF THE PLASTIC COVERING TO SECURE SUCH TOP AND FRONT PORTIONS OF THE COVERING TO THE TOP AND FRONT SURFACES OF THE ROUGH KEYBOARD, CUTTING THE KEYBOARD AND PLASTIC COVERING PIECES THEREON FROM THE GROOVES IN THE OVERHANGING EDGE OF THE COVERING PIECES AND ALONG THE MARKS ON THE ROUGH KEYBOARD WHEREBY THE INDIVIDUAL NATURAL KEYS WHEN SEVERED HAVE PARTS OF THE COVERING PIECES ON THE TOP AND FRONT SURFACES THEREOF, AND FINISHING THE INDIVIDUAL KEYS. 